Apparatus for delivering a predetermined volume of fluid at regular intervals

ABSTRACT

Fluid delivery apparatus for intermittently delivering a selected volume of fluid in which a resilient device is compressible by pressure of the fluid in a pressure chamber, a valve mounted on the resilient device being opened to deliver the fluid when a predetermined degree of compression has been achieved and being subsequently closed when the falling pressure in the pressure chamber permits a predetermined expansion.

United States Patent 1191 Grogonoet al. 1 Sept. 4, 1973 1 APPARATUS FORDELIVERING A 3.530.850 9/1970 Bird l28/l45.6

PREDETERMINED VOLUME or FLUID AT 2/1966 REGULAR INTERVALS 3,352,31911/1967 Kennedy 137/503 [75] Inventors: Alan Walter Grogono, London;FOREIGN PATENTS OR APPLICATIONS F'edemk Fmmmoxfmd, 648,191 1/1951 GreatBritain..l 128 188 both of England 227,106 0/1968 U.S.S.R 123/1456 [73]Assignee: H. G. East Company Limited,

' Oxford England Primary Examiner-Henry T. Klinksiek 22 Filed; Ju|y 22971 Assistant Examiner-Robert J. Miller [21] A l N 165 103Attorney-Robert D. Flynn et al.

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[30] Foreign Application Priority Data ABSTRACT 1970 Great Britain35667/7 Fluid delivery apparatus for intermittently delivering a vselected volume of fluid in which a resilient device is 5" xgi gzg ig fcompressible by pressure of the fluid ina pressure Field 12gb 5 145 6chamber, a valve mounted on the resilient device being 125145 7 503 bopened to deliver the fluid when a predetermined degree of compressionhas been achieved and being subsequently closed when the fallingpressure in the pres- [56] UNI TE S S I FZ I-FES SZ TENTS sure chamberpermits a predetermined expansion.

3,156,238 11/1964 Bird 128/1455 13 Claims, 1 Drawing Figure s 21 I L A 1a 25 p 1 24 29' 1 APPARATUS FOR'DELIVERING A PREDETERMINED VOLUME orrum) AT REGULAR INTERVALS This invention relates to apparatus forproviding an intermittent flow of fluid, and is particularly useful indevices used for administering artificial ventilation in which air,oxygen or other suitable gas mixture intermittently inflates a patientslungs.

It is an object of the present invention to provide apparatus which issimple and which intermittently delivers a fixed volume of fluid.

SUMMARY OF THE INVENTION The present invention is fluid deliveryapparatus including a pressure chamber, means for introducing fluidunder pressure into the chamber, resilient means in the chambercompressible by the fluid, a valve operable upon compression of theresilient means and means for actuating the valve after a pre-determinedmovement thereof to permit fluid to exhaust from the chamber.

An embodiment of the present invention will now be described, by way,'of example, with reference to the accompanying'lirawing, the singleFIGURE of which diagrammatically illustrates an artificial ventilatorfor use with a human patient.

Referring now to the drawing, a ventilator for use with a human patientwho cannot, or who finds-it difficult to, breathe for himself comprisesa pressure chamber in which is mounted a resilient bellows device 11 anda valve 12.

The chamber 10 is provided with a gas inlet 14 and 1 is gas tight at thepressures normally encountered in use.

The resilient bellows device 11 is sealed and at one end 17 is fixed toa bracket 16 on the walls of the chamber 10. The other end 18 of thebellows device 11 is free to move in the chamber and carries the valve12.

The valve 12 includes two valve members, a valve cup 19 and a valve disc20. The valve cup 19 is mounted on the end 18 of the bellows device 11and moves with it. The interior of the valve cup 19 connects with anoutlet line 21. The valve disc 20 is mounted by radial springs 24onbrackets 25 extending from the end 18 of the bellows device 11, theradial springs 24 providing a small bias of the valve disc 20 away fromthe valve cup 19. A pin 26 extends from the valve disc 20 on its sideremote from the valve cup passes through holes 27 in a bracket 28 and alever 29, and is provided with collars 30 which are large enough toengage the edges of the holes 27 and thus act as stops to limit movementof the pin 27 and valve disc 20 towards the right and left respectivelyas seen in the drawing. The lever 29 has'a fixed pivot 32 at one end andat its other end engages a cam33 rotatable by a knurled control knob 34.v

The outletline 21 branches into two lines 35and 36, one of which 35,isprovided with a flow control valve 38 and the other of which, 36,terminates in a bellows valve 39. i i In use the gas inlet 14 isconnected to a suitable supply of pressurised gas, for example apressure bottle,

11 is expanded so that the valve cup 19 is in engagement with the valvedisc 20 whose movement to the right has been restricted by engagement ofa collar 30 with the bracket 28. As the pressure in the chamber 10builds up, the bellows device 11 is compressed and'its end 18 moves tothe left as seen in the drawing. The valve disc 20 remains in engagementwith the valve cup 19 as the pressure differential between the sides ofthe valve disc 20 maintaining such engagement is greater than the forceexerted by the radial springs 24 tending to part the valve disc and cup.Compression of the bellows device 11 continues until engagement of thelever 29 with a collar 30. No further movement then occurs until thepressure in the chamber 10 has increased slightlyand the force due tothe pressure differential between the faces of the end 18 of the bellowsdevice over the annular area around the valve cup 19 has increased tocompensate for the force on the valve disc that has been taken up by thelever 29 and is no longer effective on the bellows device. When thepressure has built up sufficiently the valve springs open under theinfluence of the springs 24 and the increased pressure on the inside ofthe valve cup 19. The gas in the chamber passes to the outlet line 21and thence through the line 36 to the bellows valve 39, to close theexpiratory line from the patient, and, via the valve 38 to the patientto inflate the patients lungs.

Gas flowing from the outlet line 21 causes the pressure in the chamber10 to decrease causing a corresponding expansion of the bellows device.As the end 18 of the bellows device moves to the right it takes with itthe brackets 25 and the valve disc 20 until the collar 30 engages thebracket 28. The bellows device continues to expand and closes the valvecup 19 against the stationary valve disc 20.

The pressure on either side of the bellows valve 39 now equalises, thevalve 39 opens and the patie'nts lungs deflate; Meanwhile pressure inthe chamber 10 is increasing and, when the valve 12 reopens deflation isterminated and inflation of the patients lungs recommences.

It should be noted that the ventilator is essentially a constant volumedevice opprating as it does on pressure differentials with aconstantvolume, i.e., the pressure chamber. The volume passed in eachcycle can however be varied by adjustment of the knob 34 and thereby ofthe cam 33 and the lever 2 9t hus effectively adjusting the travel ofthe pin 26. It should also be noted that the ventilator is extremelysimple and is stable in both the open and closed positions.

Modifications may be made to the embodiment described. It may bedesirable to ensure positive operation of the valve 12 by including inthe line 21 a pressure opening non-return valve 41.. Also it may beconvenient to have access to the interior of the bellows to permitpressurisation thereof during manufacture for calibration purposes.Moreover the pressure chamber may be fitted with a heating element tovapourise water in the chamber. This arrangement permits humidificationof gases leaving the chamber as well as sterilisation of the apparatusby boiling.

The ventilator may be adapted so that its operation is initiated by anexternal signal such as a change in pressure at the outlet caused byattempts by the patient to breathe. This can be achieved by renderingthe stop involving the lever 29 inoperative, limiting the gas pressurein the chamber, and providing a conventional lever arrangement to changethe pressure change, caused by a patient attempting to breathe into aforce sufficient to open the valve 12.

The invention has been described in relation to a ventilator but isequally applicable in any system where intermittent supply of specifiedvolumes of fluid is desired.

We claim:

1. Fluid delivery apparatus including:

a pressure chamber;

means for introducing fluid under pressure into the chamber;

resilient means in the chamber compressible by the fluid as the fluidpressure in the chamber increases;

a valve mounted on the resilient means and movable upon compression ofthe resilient means within the chamber; and

means for actuating the valve after a predetermined movement thereof topermit fluid to exhaust from the chamber.

2. Apparatus as claimed in claim 1, in which said valve comprises twomembers mounted on .the resilient means, said two members being movablerelative to each other and biased apart.

3. Apparatus as claimed in claim 2, in which said actuating meansincludes at least one stop to limit movement of one of the valve membersin the chamber.

4. Apparatus as claimed in claim 3, in which said stop is variable.

5. Apparatus as claimed in claim 4, in which said resilient meanscomprises a bellows device, one end of which is fixed in the chamber andthe other end of which carries the valve members.

6. Apparatus as claimed in claim 5 in which said one of the valvemembers is a valve disc and the other of said valve members is a valvecup secured to said other end of the bellows device.

7. Apparatus as claimed in claim 6, comprising a fluid outlet line fromthe chamber which communicates with the interior of the valve cup andincludes a further pressure opening non-return valve.

8. Apparatus as claimed in claim 7, in which the outlet line branches,one branch including a flow control and serving as a line to exhaustfluid under pressure from the chamber and the other branch terminatingin a valve which closes said other branch during exhaust of fluid underpressure from the chamber via said one branch, and which opens saidother branch after exhaust of fluid under pres-sure from the chamber isterminated.

9. Apparatus as claimed in claim 1 in which said chamber includes meansfor evaporating water.

10. Apparatus as claimed in claim 8, wherein said other branch isadapted to receive input fluid to the chamber when the valve terminatingsaid other branch is open.

11. Apparatus as claimed in claim 1, in which said resilient meanscomprises a bellows device. one end of which is fixed in the chamber andthe other end of which carries the valve.

12. Apparatus as claimed in claim 11, in which said valve comprises twomembers mounted on the. resilient means, said two members being movablerelative to each other and biased apart, one of the valve members beinga valve disc and the other of said valve members being a valve cupsecured to said other end of the bellows device.

13. Apparatus as claimed in claim 1, comprising a fluid outlet line fromthe chamber which is operatively controlled by the valve, the outletline branching into two branches, one branch including a flow controland serving as a line to exhaust fluid under pressure from the chamberand the other branch terminating in a valve which

1. Fluid delivery apparatus including: a pressure chamber; means forintroducing fluid under pressure into the chamber; resilient means inthe chamber compressible by the fluid as the fluid pressure in thechamber increases; a valve mounted on the resilient means and movableupon compression of the resilient means within the chamber; and meansfor actuating the valve after a predetermined movement thereof to permitfluid to exhaust from the chamber.
 2. Apparatus as claimed in claim 1,in which said valve comprises two members mounted on the resilientmeans, said two members being movable relative to each other and biasedapart.
 3. Apparatus as claimed in claim 2, in which said actuating meansincludes at least one stop to limit movement of one of the valve membersin the chamber.
 4. Apparatus as claimed in claim 3, in which said stopis variable.
 5. Apparatus as claimed in claim 4, in which said resilientmeans comprises a bellows device, one end of which is fixed in thechamber and the other end of which carries the valve members. 6.Apparatus as claimed in claim 5 in which said one of the valve membersis a valve disc and the other of said valve members is a valve cupsecured to said other end of the bellows device.
 7. Apparatus as claimedin claim 6, comprising a fluid outlet line from the chamber whichcommunicates with the interior of the valve cup and includes a furtherpressure opening non-return valve.
 8. Apparatus as claimed in claim 7,in which the outlet line branches, one branch including a flow controland serving as a line to exhaust fluid under pressure from the chamberand the other branch terminating in a valve which closes said otherbranch during exhaust of fluid under pressure from the chamber via saidone branch, and which opens said other branch after exhaust of fluidunder pres-sure from the chamber is terminated.
 9. Apparatus as claimedin claim 1 in which said chamber includes means for evaporating water.10. Apparatus as claimed in claim 8, wherein said other branch isadapted to receive input fluid to the chamber when the valve terminatingsaid other branch is open.
 11. Apparatus as claimed in claim 1, in whichsaid resilient means comprises a bellows device, one end of which isfixed in the chamber and the other end of which carries the valve. 12.Apparatus as claimed in claim 11, in which said valve comprises twomembers mounted on the resilient means, said two members being movablerelative to each other and biased apart, one of the valve members beinga valve disc and the other of said valve members being a valve cupsecured to said other end of the bellows device.
 13. Apparatus asclaimed in claim 1, comprising a fluid outlet line from the chamberwhich is operatively controlled by the valve, the outlet line branchinginto two branches, one branch including a flow control and serving as aline to exhaust fluid under pressure from the chamber and the otherbranch terminating in a valve which closes said other branch duringexhaust of fluid under pressure from the chamber via said one branch,and which opens said other branch after exhaust of fluid under pressurefrom the chamber is terminated.